Projection system

ABSTRACT

A projection system having a set of projectors that cast images: (i) outwards onto the concave surface of a hemispherical dome, as is usual in planetariums and (ii) inward onto the convex surface of a centrally located sphere. The images thus cast may be coordinated by a controlling computer program, so that changes in the content or orientation of the images on the sphere result in corresponding changes in the images on the dome and vice versa.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/206,426, filed Jan. 30, 2009, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

This invention relates to projection systems for domed spaces, includingplanetariums, and more particularly, to a combined convex-concaveprojection system. The present invention also includes systems withapplication to full-dome immersive media in general.

BACKGROUND OF THE INVENTION

A planetarium is a facility for the display of celestial bodies. Foralmost a century, planetariums have employed analog projection systems,sometimes referred to as an opto-mechanical star ball or globe. The starball shines rays of light either through apertures and/or lenses onto asurface. In some cases, the surface is the concave surface formed by theceiling or inner surface of a dome. This projector would typically becentrally located with respect to the dome in order to project anaccurate image throughout the dome. In general, the apertures and/orlenses are defined within a star field plate, which sets the relativepositions of the depicted celestial bodies. Such devices may be geardriven about gimbaled axes to simulate the natural keplerian patterns ofcelestial bodies in a desired movement with appropriate relativepositions. In this way, different times, latitudes, orbital variables,etc., may be illustrated.

Early alternatives to opto-mechanical projection systems involved filmdisplay and wide angle lenses. Recently, digital projectors have begunto replace opto-mechanical devices. Some digital projectors arecentrally located and project light onto the dome using a fish-eye lens.Others are located off-center and cast images onto the ceiling viareflection off an optically centered hemispheric mirror. In either case,they can create a vacancy in the center of the planetarium where thelarge opto-mechanical device used to be.

Thus, conventional planetarium projection systems generally include: (i)systems with a centrally located opto-mechanical star ball that projectspoints of light representing stars and discs of light representingplanets, moon, and sun, onto the concave side of a white-painteddome-shaped ceiling; (ii) systems with a centrally located (or slightlyoff-center) digital projector with a fish-eye lens that projects digitalimages onto said dome; and (iii) systems with one or more peripherallylocated digital projectors that project a computer-warped digital imagevia a reflection off a hemispheric mirror onto said dome.

Because centrally located digital projection systems can be aligned withthe pole of the dome, such systems may have less distortion. This canreduce the software, optics, and hardware expense, aiding in full domecoverage. Depending on the projector, central projection may have somecolor separation. Peripherally located digital projection systems freeup the center of the domed space, but may be subject to distortion orgaps in coverage; peripheral projection is more complicated and mayrequire additional software and hardware. Some peripheral systemsrequire multiple projectors for full dome coverage.

Full-dome projection systems are of value in presenting informationabout the celestial bodies. However, it is difficult to convey to aplanetarium audience the relationship between a view of the cosmosprojected onto a dome and the location or perspective that such a viewrepresents. The planetarium director is often limited to a verbal ornumerical description of the latitude and longitude of an earth basedperspective. Further, with non mechanical systems, the potential forchanging the perspective to include non-earth based locations arises,even within a single showing; a particular planetary alignment, forexample, may be viewed from a variety of perspectives.

Thus there is the opportunity to improve projection systems bysynchronizing the inward and outward projected images, which wouldenable better visualization. In addition, there is a need for aprojection system that enables visualization from a variety ofviewpoints. Such a system would be useful also for full-immersivesimulations and video beyond application as planetariums, astronomy, orplanetary sciences. Aside from clear entertainment value, it iscontemplated that such a system would have considerable value foreducation in geophysics, structural geology, physics (e.g., nuclearparticles); chemistry (e.g., atoms, molecules, and nano-structures);biology (e.g., visualization of cells and organelles).

SUMMARY OF THE INVENTION

An aspect of embodiments of the present planetarium projection system isthe pairing of concave (full-dome) projection systems with convex(spherical) projection systems and to coordinate the images thusprojected in order to convey to the planetarium audience the spatialrelationship between the cosmic scene portrayed on the dome and thecurrent position and orientation of the celestial body (earth, moon,planet, sun etc) of the viewpoint.

The present invention provides a planetarium comprising a digitalprojection device or set of devices casting images on the concave sideof the planetarium dome, a set of digital projection devices castingimages on the convex side of a centrally located spherical screen, and amain computer running software that controls and coordinates allprojected images.

Among other things, the present invention as described above has severalaspects as described below:

(a) synchronization of the inward and outward projected images so thatthe planetarium audience is better able to visualize the significance ofthe cosmic scene and the relationship between the viewpoint of theobserver and the scene that is observed.

(b) projection of the view from any viewpoint such as, but not limitedto, the view from any point on the surface of the Earth (i.e., asopposed to a traditional geocentric view of the cosmos projected onto aAristotelian celestial sphere); the view from any point on the surfaceof any planet, moon, asteroid or comet; the view from any point on thesurface of the sun; the view from the center of the Earth, sun, moon orany celestial body, with coordination between said view and the image ofthe viewpoint as projected onto the central sphere.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an embodiment of the projection system, along anorth-south or east-west cross section.

FIG. 2 is another embodiment of FIG. 1

FIG. 3 is a plan view of the system in FIG. 1

FIG. 4 shows the extent of the outward projection from the fish-eye lensprojector onto the concave dome.

FIG. 5 shows the extent of the inward projection of a typical peripheralprojector onto the central convex sphere.

FIG. 6 illustrates the coordination of images projected onto the domeand the sphere.

FIG. 7 is an optional aspect of embodiments of the system.

FIG. 8 is an aspect of an embodiment of the projection system.

DETAILED DESCRIPTION

An aspect of the projection system is to introduce a sphericalprojection system into a dome or planetarium to convey the relativeorientation and relationships of celestial bodies. Given the limitationsof conventional digital projection systems, the present system involvesuse of a convex (spherical) projection system with embodiments of aconcave (full-dome) projection system; the images projected by suchsystems may be coordinated in order to convey to an audience the spatialrelationship between the depicted celestial bodies. This enables theclear illustration of relative positioning, ‘especially given digitalprojection systems’ adaptability for display with the plurality ofperspectives. Thus, spherical projection systems are of value inpresenting information related to the relation of proximate celestialobjects, such as the relative position, rotation, motion, etc., of theearth to the moon, sun, or other planets.

The variability means that a depiction may alternately display from aperspective from earth followed by the perspective from the othercelestial object, which in turn may be followed by a completelydifferent set of images for other celestial bodies. Importantly, theimage projected onto a central sphere may change from geocentric toheliocentric or to any planet or moon, scaffolding the observer'sexploration of difficult concepts such as retrograde planet “wandering.”As another example, an oscillating image projected onto a sphere mightrepresent the plane of motion of a Foucault pendulum, while a rotatingprojection low on the dome may show a physical Foucault pendulumswinging and undergoing precession.

Embodiments of spherical projection systems may include: (i) systemswith a set of projectors for projection onto the convex outer surface ofa reflective or white-painted sphere, typically with the set ofprojectors often located high on the walls of the room containing thesphere; or (ii) systems in which projection onto the surface of atransparent sphere originates from inside the sphere. Some sphericalprojection systems using the former approach locate those projectors inrooms other than the dome.

Embodiments according to the present approach will be describedhereinafter with reference to the accompanying drawings. FIG. 1illustrates an embodiment of a projection system [100] for aplanetarium. In this embodiment, a dome [105] is shown having a concaveinterior with a lower side wall [110] at its lower wall end [115]. Thedome [105] interior is bounded by the dome inner surface [120] of thedome interior. Preferably, the dome inner surface [120] will have adesired diffuse reflectivity suitable for receipt of projected images[125]. Diffuse in this sense is to contrast with specular or simply areflectivity that would be unsuitable for use as a projection screen. Adome projector [130] is situated within the dome [105], oriented toproject at least a first dome projected image [140] (not shown) at leastpartially onto the inner surface [120] of the dome [105]. For example,the reference axis [135] projected image [125] of the dome projector[130] is indicated with a vertical arrow. The dome projected image [125]is distributed across the dome inner surface [120] of the planetariumdome [105]. In this way, dome projector [130] may produce a first domeprojected image [140] (shown as an arrow) on the dome inner surface[120].

A reflective sphere [145] is shown at a central point within the dome[105]. Reflective sphere [145] may be comprised of metal, ceramic,glass, plaster, plastic, wood, or other material capable of presenting asphere outer surface [150] having a desired reflectivity. Preferably,the sphere outer surface [150] will have a desired diffuse reflectivitysuitable for receipt of at least a first projected image [140]. Thereflective sphere [145] may be painted white or gray on the sphere outersurface [150] so as to enable a diffuse reflectivity like that of aprojection screen.

In the embodiment of FIG. 1, a central base [155] is provided, which maybe in the form of sufficient structure for supporting the reflectivesphere [145] and dome projector [130] at a desired height. Central base[155] may take a variety of forms, such as a pedestal or plinth, acolumn, a rigid rod or support connected to reflective sphere [145], afixed point of attachment to some other structure such as the floor[180]. Central base [155] may be of any sufficiently rigid material forthis function, such as metal, ceramic, glass, plaster, plastic, wood, orother suitable material. Alternatively, reflective sphere [145] may besupported by guylines or wires, so long as the quality of the sphereprojected image [175] is acceptable.

In the embodiment shown, central base [155] supports the primary domeprojector [130] and reflective sphere [145]. In this embodiment,reflective sphere [145] is shown as comprising a shell that defines areflective sphere interior space [160] of reflective sphere [145]. Domeprojector [130] may be disposed within the reflective sphere interiorspace [160] at least partially. The degree to which dome projector [130]is disposed within interior space [160] is a trade off between thepotential of interference with any sphere projected images [125] on thesphere outer surface [150] of reflective sphere [145] and theconvenience of access to the dome projector [130]. Reflective sphere[145] may be constructed in parts capable of being fastened together orunfastened so that access can be had to the enclosed dome projector[130] for service. Alternatively, reflective sphere [145] may simplyhave sufficient doors or panels (not shown) providing access to domeprojector [130]. As may be seen in FIG. 1, primary dome projector [130]is oriented within reflective sphere [145] so as to project through aprojection port at least partially onto the dome inner surface [120].For this embodiment, a lens [165] such as a fisheye lens may be disposedat the output of dome projector [130] in order to increase coverage ofthe projected image [125] onto the dome inner surface [120].

A plurality of peripheral projectors [170] may be disposed about thelower side wall [110]. For convention, each projector projects anindividual projection [125]. The plurality of peripheral projectors[170] may be disposed about the lower side wall [110] of the dome [105]at substantially equidistant points, with each of the peripheralprojectors [170] oriented so as to project complementary individualprojections [125] onto the sphere outer surface [150] of the reflectivesphere [145] and adapted to produce a sphere projected image [175] (notshown) corresponding to at least one celestial body on the sphere outersurface [150]. Substantially equidistant simply means sufficientlyregularly spaced so as to project onto reflective sphere [145] withdesired complementing image portions or individual projections [125].The individual peripheral projectors [175] may project with someoverlap, for example, so long as the final quality of sphere projectedimage [175] is acceptable. In addition, computer software controlprogram may accommodate some irregularities to enhance the sphere image[175] to some extent. In addition, other desired lenses [165] maycompensate for some irregularities. The peripheral projectors [170] mayhave lenses [165] such as telescopic lenses, with the reference axis[135] of their projected image portions [125] indicated by the shownarrows shown pointing inwards towards the convex sphere outer surface[150] of the centrally mounted reflective sphere [145].

In this way, the relative position of a first celestial body depictedwithin the first dome projected image [140] on the dome inner surface[120] to a second celestial body depicted by the first sphere projectedimage [175] on the sphere outer surface [150] is adapted to illustrate adesired spatial relation between the first and second celestial bodies.

FIG. 2 illustrates a different embodiment of the projection system [100]within dome [105]. In this example, dome projector [130] is notcentrally mounted, but disposed near a lower side wall [110]. The domeprojector [130] may project individual projection [125] onto the concavedome inner surface [120] of dome [105]. The dome projector [130]individual projection [125] is directed to a planar mirror [205] in amirror shroud [210]. A first reflected image [215] (shown by the arrow)is then reflected onto a hemispheric mirror [220]. The individualprojection [125] is then directed to the dome inner surface [120]. Thedome projector [130] projection path may be direct or indirect via oneor more mirrors to the dome inner surface [120], as shown. In thisembodiment, there is no central lens [165] and the reflective sphere[145] may be solid.

FIG. 3 shows a plan view of an embodiment of the projection system[100]. In this example, lens [165] is illustrated as a fisheye lens withreflective sphere [145], illustrating that dome projector [130] (notshown) is according to the configuration of FIG. 1, within reflectivesphere [145]. As shown in this case, four peripheral projectors [170]are provided. Two peripheral projectors [170] are disposed about thelower side wall [110] on a north-south axis and two peripheralprojectors [170] are disposed about the lower side wall [110] on aneast-west axis. Other arrangements of peripheral projectors [170] willsuffice so long as the individual projections [125] are directed ontoreflective sphere [145] in a desired manner to provide a preferablynear-full, coverage of the sphere outer surface-[150] exposed or visibleto viewers.

FIG. 4 shows a side view of an embodiment of the projection system[100]. In this case, the width of the individual projection [125]emerging from (fish eye) lens [165] from the dome projector [130] isshown for an embodiment of dome projection according to FIG. 1. Theilluminated region is shown in above the phantom line and thenon-illuminated region below. The lens [165] casts a individualprojection [125] over most of the dome interior surface [120] of thedome [105]. In this embodiment the angle of coverage shown was170-degrees+/−, which was achieved for a dome [105] with a radius of 20feet.

FIG. 5 shows a side view of an embodiment of the projection system[100]. In this case, the width of the projected light emerging from the(telephoto) lens [165] of a typical peripheral projector [170] is shownincident onto the convex sphere outer surface [150] of centrally locatedreflective sphere [145]. Each peripheral projector [170] may light orilluminate a complementary portion of the reflective sphere [145]. Acomputer software control program may be used to coordinate an overlapand “stitching” or combining of the plurality of complementaryindividual projections [125]. The control program may reside or berecorded on memory in communication with at least one computer processorwhich, in turn, would be in communication with the plurality ofperipheral projectors [170]. Optionally, computer processor would be incommunication with and control the primary dome projector [130] as well.

FIG. 6 shows a side view of an embodiment of the projection system[100]. This figure illustrates the coordination of peripheral projectors[170] with dome projector [130]. For example, at a first time theperipheral projectors [170] create a first sphere projected image [175],such as the celestial body of the Earth, on the centrally locatedreflective sphere [145] with the Earth's pole projected at Earthposition [605]. Dome projector [130] may create a full dome image withthe celestial body star Polaris projected at the first Polaris point[610] on the dome inner surface [120] of dome [105]. Projected imageline [615] illustrates the relation between the celestial bodies withpoints [605] and [610], in the direction of a radius of the dome [105].

At a second, later time, the user may choose to rotate the image of theEarth so that its pole now projects at Earth point [620] (i.e., a secondsphere projected image). A control program may automatically move theimage on the full dome [105] so that the star Polaris now projects atPolaris point [625] (i.e., a second dome projected image). Secondaryprojected image line [630] illustrates the relation between thecelestial bodies with points [620] and [625], in the direction of aradius of the dome [105]. The control program may achieve thiscoordination by means of quaternion operations.

FIG. 7 shows a top view of an optional aspect for embodiments of theprojection system [100]. One or more mobile screen stands [705] orrovers [710] is provided. Rover [710] refers to mobile screen standsconfigured for transport along a desired path. In some embodiments,rovers [710] may be mounted on wheels with extendible arms and roboticmotion controls. However, other transport mechanisms are available andthe system herein is not so limited. The rovers [710] may carry avariety of 2-dimensional or 3-dimensional reflective screens [715]abound the interior of the dome [105]. For example, as shown in FIG. 7,such a desired path may be along aisles [720] when attendees are seatedin place; if seating is removed, a more diverse path may be available.One or more rover projectors [725] may be disposed about dome [105], inlocations appropriate for the path of rovers [710]. A computer controlprogram may coordinate the roving projected images (not shown) on themobile screens [705] as appropriate. The computer control program mayreside on the memory of a computer in communication with the roverprojectors [725] and the rovers [710].

FIG. 8 is an example of the projection system [100] with an image of theearth projected onto the reflective sphere [145] while stars visiblefrom earth's zenith are projected onto the dome inner surface [120] ofdome [105]. A computer processor with a memory is shown in communicationwith peripheral projectors [170] and dome projector [130].

The projection system [100] of the present invention may extend to acomputer readable medium storing a computer program for use with a dome[105] having a concave inner surface [120] and a side wall [110] at itslower end [115]. The dome [105] interior with an inner surface [120] hasa desired diffuse reflectivity and a reflective sphere [145] mounted ata central point within the concave interior of the dome [105]. Thereflective sphere [145] having a sphere outer surface [150] of a desireddiffuse reflectivity. The computer readable medium may store controlprogram code for receiving and storing data about the relativeorientation of at least a first celestial body to a second celestialbody, the data representing a plurality of images. Preferably, therelative orientation changes extend to a variety of changes, such askeplerian motion, changes in perspective, rotation of a celestial body,etc. The computer readable medium may also store control program codefor controlling a primary dome projector [130] situated within the dome[105], and oriented so as to project at least partially onto the domeinner surface [120] of dome [105], and adapted to produce a first domeprojected image [140] of the first celestial body on the dome innersurface [120]. The computer readable medium may also store a controlprogram code for controlling one or more peripheral projectors [170],the peripheral projectors [170] being disposed about the lower side wall[110] of the dome (optionally at substantially equidistant points), witheach of the peripheral projectors [170] oriented so as to project oncomplementary portions of the sphere outer surface [150] of thereflective sphere [145], and adapted to produce a first sphere projectedimage [175] on reflective sphere [145] corresponding to the secondcelestial body on such sphere outer surface [150]. Upon receipt of aninstruction corresponding to a change in relative orientation of thefirst and second celestial bodies, the control program code may apply aquaternion operation for creating a subsequent (e.g., a second) domeprojected image [140] on the dome inner surface [120] and a subsequent(e.g., a second) sphere projected image [805] (not shown) on reflectivesphere [145] to illustrate the change in orientation of the firstcelestial body to the second celestial body. The computer medium mayalso include control program code adapted to the variations in theprojection system [100] discussed above.

It is to be understood that various modifications and variation of thespecific embodiments described herein will be readily apparent to thoseskilled in the art in light of the above teachings without departingfrom the spirit and scope.

1. A projection system for use within a dome having a concave interiorand a side wall at its lower end, the dome interior having an innersurface with a desired diffuse reflectivity, the system comprising: (i)a reflective sphere mounted at a central point within the concaveinterior of the dome, the reflective sphere having an outer surface of adesired diffuse reflectivity; (ii) a dome projector situated within thedome, and oriented so as to project at least partially onto the domeinner surface of the dome, and adapted to produce a first dome projectedimage of a first celestial body on the dome inner surface; (iii) aplurality of peripheral projectors, the peripheral projectors disposedabout the lower side wall of the dome, with each of the peripheralprojectors oriented so as to project on complementary portions of theouter surface of the reflective sphere, and adapted to produce a firstsphere projected image corresponding to a second celestial body on theouter surface of the reflective sphere; and (iv) wherein the relativeposition of the first dome projected image on the inner surface of thedome to the first sphere projected image on the outer surface of thereflective sphere is adapted to illustrate a desired orientation betweenthe first and second celestial bodies.
 2. The projection system of claim1, further comprising: (i) a computer processor in communication withthe dome projector and the plurality of peripheral projectors; and (ii)a memory in communication with the computer processor, the memory forrecording a control program for directing the primary dome projector andthe plurality of peripheral projectors so as to produce the first domeprojected image and the first sphere projected image in a desiredmanner.
 3. The projection system of claim 1, further comprising: (i) acomputer processor in communication with the dome projector and theplurality of peripheral projectors; (ii) a first memory in communicationwith the computer processor for storing data about the relativeorientation of at least the first celestial body to the second celestialbody, the data representing a plurality of images; (iii) a second memoryin communication with the computer processor, the memory for recording acontrol program for directing the dome projector and the plurality ofperipheral projectors; and (iv) wherein, upon the receipt of aninstruction corresponding to a change in relative orientation of thefirst and second celestial bodies, the control program applies aquaternion operation for creating a second dome projected image and asecond sphere projected image to illustrate the change in orientation ofthe first celestial body to the second celestial body.
 4. The projectionsystem of claim 1, wherein the plurality of peripheral projectors aredisposed at substantially equidistant points about the lower side wallof the dome.
 5. The projection system of claim 1, further comprising ahemispheric mirror, and wherein the dome projector is peripherallymounted with the hemispheric mirror configured within the path of thedome projector output, so that the dome projector is able to project atleast partially onto the hemispheric mirror, and the dome projector andhemispheric mirror are configured so as to project onto the dome innersurface to produce the first dome projected image of a first celestialbody on the inner surface.
 6. The projection system of claim 1, wherein:(i) the reflective sphere comprises a shell that defines an interiorspace; and (ii) the dome projector is disposed at least partially withinthe interior space of the dome, and is oriented so as to project atleast partially onto the dome inner surface of the dome.
 7. Theprojection system of claim 1, further comprising: a fish eye lens;wherein the reflective sphere comprises a shell that defines andsurrounds an interior space, the shell having a projection port at anupper end of the reflective sphere; and wherein the dome projector isdisposed within the interior space, and is oriented so as to projectthrough the projection port, through the fish eye lens, and at leastpartially onto the dome inner surface.
 8. The projection system of claim1, further comprising: (i) at least one mobile screen configured fortransport along a desired path; and (ii) at least one mobile screenprojector.
 9. The projection system of claim 1, further comprising: (i)a computer processor in communication with the dome projector and theplurality of peripheral projectors; (ii) a first memory in communicationwith the computer processor for storing data about the relativeorientation of at least the first celestial body to the second celestialbody, the data representing a plurality of images; (iii) a second memoryin communication with the computer processor, the memory for recording acontrol program for directing the dome projector and the plurality ofperipheral projectors; (iv) at least one mobile screen configured fortransport along a desired path; (v) at least one mobile screen projectoradapted to project at least partially onto the at least one mobilescreen, wherein the computer processor is further in communication withthe mobile screen and at least one mobile screen projector, and whereinthe control program is adapted to directing the transport of the atleast one mobile screen and for directing the at least one mobile screenprojector; (vi) a third memory in communication with the computerprocessor, the memory for storing data about representing a plurality ofprojected images suitable for the mobile screen; (vii) wherein, upon thereceipt of a first instruction corresponding to a change in relativeorientation of the first and second celestial bodies, the controlprogram applies a quaternion operation for creating subsequent projectedimages to illustrate the change in orientation of the first celestialbody to the second celestial body; and (vii) wherein, upon the receiptof a second instruction relative to the creation of a mobile image, thecontrol program applies a projected image suitable for the mobile screenfrom the at least one mobile screen projector onto the at least onemobile screen.
 10. A computer readable medium storing a computer programfor use with a dome having a concave interior and a side wall at itslower end, the dome interior with an inner surface having a desireddiffuse reflectivity and a reflective sphere mounted at a central pointwithin the concave interior of the dome, the reflective sphere having anouter surface of a desired diffuse reflectivity, the computer readablemedium comprising: (i) a control program code for receiving and storingdata about the relative orientation of at least a first celestial bodyto a second celestial body, the data representing a plurality of images;(ii) a control program code for controlling a dome projector situatedwithin the dome, and oriented so as to project at least partially ontothe inner surface of dome, and adapted to produce a first projectedimage of the first celestial body on the inner surface of dome; (iii) acontrol program code for controlling two or more peripheral projectors,the peripheral projectors being disposed about the lower side wall ofthe dome, with each of the peripheral projectors oriented so as toproject on complementary portions of the outer surface of the reflectivesphere, and adapted to produce a first sphere projected imagecorresponding to the second celestial body on such outer surface; (iv)wherein, upon receipt of an instruction corresponding to a change inrelative orientation of the first and second celestial bodies, thecontrol program code applies a quaternion operation for creating asubsequent projected image from the data to illustrate the change inorientation of the first celestial body to the second celestial body.11. The computer readable medium of claim 10, wherein the plurality ofperipheral projectors are disposed at substantially equidistant pointsabout the lower side wall of the dome.
 12. The computer readable mediumof claim 10, wherein the dome projector further comprises a hemisphericmirror, and wherein the dome projector is peripherally mounted alongwith the hemispheric mirror, the hemispheric mirror being configuredwithin the path of the dome projector output, so that the dome projectoris able to project at least partially onto the hemispheric mirror, andthe dome projector and hemispheric mirror are configured so as toproject onto the interior surface to produce the first dome projectedimage of a first celestial body on the inner surface.
 13. The computerreadable medium of claim 10, wherein the reflective sphere comprises ashell that defines an interior space; and the dome projector is disposedat least partially within the interior space, and is oriented so as toproject at least partially onto the inner surface of the dome.
 14. Thecomputer readable medium of claim 10, wherein the dome projector furthercomprises a fish eye lens; wherein the reflective sphere comprises ashell that defines and surrounds an interior space, the shell having aprojection port at an upper end of the sphere; and wherein the domeprojector is disposed within the interior space, and is oriented so asto project through the projection port, through the fish eye lens, andat least partially onto the inner surface of the dome.
 15. The computerreadable medium of claim 10, wherein the dome further comprises at leastone mobile screen configured for transport along a desired path and atleast one mobile screen projector adapted to project at least partiallyonto the at least one mobile screen, wherein the computer readablemedium further comprises: (i) control program code for directing thetransport of the at least one mobile screen and for directing the atleast one mobile screen projector, wherein, upon the receipt of aninstruction relative to the creation of a mobile image, the controlprogram applies an image suitable for the mobile screen from the atleast one mobile screen projector onto the at least one mobile screen.